Iowa DNR
BioNet
River & Stream Biological Monitoring
Fish and Benthic Macroinvertebrate Surveys
Physical Habitat Assessments

Beaver Creek Johnston

Analysis Summary for Series #1487

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 46 8.85
SH Total Taxa 12 5.29
MH EPT Taxa 24 8.89
SH EPT Taxa 9 6.12
MH Sensitive Taxa 11 10
SH Ephem % 31.96 4.09
SH EPT % 41.9 4.39
SH Chiron % 55.06 4.54
SH Scraper % 8.05 1.8
SH Top3Dom % 81.73 2.9
SH Dom FFG % 79.53 3.41
MHBI 5.21 6.63
*Mouse-over metric for full name
**Final IBI is sum of scores multiplied by 0.8333

Analysis Factors

Factor Value
BMIBI Type Warm Water
Sample Date 8/19/2013
Sampling Series Series #1487
Drainage Area (mi2) 358
Log(DA) 2.55388302664387
Calculation Last Updated 7/22/2025 3:31:47 PM
Sampling Gear ArtSub
BMIBI Score
56
Warm Water
Good

BMIBI Score Explained

This site was analyzed using the BMIBI-Warm Water assessment methodology.

Sites that score between 56 - 75 are considered good. A slight reduction in number (Ephemeroptera, Plecoptera, Trichoptera) of taxa; however, good numbers of taxa are present, including several sensitive species, EPT taxa are fairly diverse and dominate the community. The most sensitive taxa and some habitat specialists may not be present and/or are reduced in abundance. The community is balanced, with no taxon excessively dominating in abundance. One functional feeding group, often collector filterers or collector gatherers, may be somewhat dominant.

This location has been classified as a survey site. Survey sites are compared to reference sites within the same ecoregion. A reference site represents natural stream qualities that are least disturbed by human activities within the watershed. Reference sites are grouped by ecoregion to establish a benchmark against which these survey streams are compared.

EcoRegion Comparison

Scores for a sampling session are compared against reference sites within the same ecoregion:

Des Moines Lobe

This site is in the Des Moines Lobe ecoregion.

Ecoregion Map
Max 84
75th Percentile 68
Median 59
25th Percentile 51
Min 10
This Session's Score 56
Total Reference Site Samples 161
Mean 58.18
Standard Deviation 13.09